Maatschappelijk verantwoord ondernemen (MVO) en reputatie

In dit artikel introduceren wij een maatstaf waarmee de reputatie voor Maatschappelijk Verantwoord Ondernemen (MVO-R) kan worden gemeten. Met behulp van deze maatstaf wordt vervolgens voor 2.447 ondernemingen uit 29 landen de MVO-Reputatie bepaald. De data die gebruikt is om de MVO-R scores te berekenen bestaat uit MVO scores van internationale rating agencies, die per onderneming betrekking hebben op circa 177 aspecten van MVO. Uit het empirisch onderzoek blijkt dat: i) ondernemingen gemiddeld genomen meer dan voldoen aan de MVO verwachtingen die geschapen zijn door de ondernemingen zelf; ii) er in Europa het hoogst wordt gescoord op MVO Reputatie, met Groot Brittannië en Finland als leiders; iii) dat de utility sector het best scoort en dat ‘gezondheidszorg’ en ‘financiële instellingen’ het slechtst scoren op MVO-Reputatie

The release of dormancy, a wake-up call for seeds to germinate

Seed dormancy determines the timing of germination, thereby contributing to successful seedling establishment and plant fitness. The induction and release of dormancy are controlled by various regulators like plant hormones and dormancy proteins. The relative strengths of these regulators are influenced by environmental factors during seed maturation and storage. In the last few years additional processes have been identified to be involved in the release of dormancy during seed storage with an important role for non-enzymatic oxidative reactions. However, the relations between the different dormancy regulators are not fully understood yet. Finally, all accumulated information will be processed in the seed during early seed imbibition and lead to the decision to germinate or not

USCID 14th technical conference

Presented at Contemporary challenges for irrigation and drainage: proceedings from the USCID 14th technical conference on irrigation, drainage and flood control held on June 3-6, 1998 in Phoenix, Arizona.Includes bibliographical references.Water properties, such as the viscosity and surface tension, can be affected by temperature and surfactants to increase infiltration rates into soils. Specifically, they will change the hydraulic conductivity of the soil. A simple soap solution and the new material PAM (inexpensive polymer chemical) were evaluated as surfactants. Laboratory experiments and field tests on a site in Davis, California were done to quantify the effects of changing the water properties. Additional effects, like the improved soil structure during infiltration and less soil particles in tailwater (reduced erosion due to runoff) were observed and are described in this paper. The conclusions of this study are translated into suggestions for improved on-farm water use in furrows, sprinklers, and drip irrigation

Potential for up-scaling Nimr reed bed facilities, Oman : feasibility study

This report describes the findings of a feasibility study to treat oil contaminated water using reed beds, and consume the treated saline water using forestry. The feasibility study focused on the social, technical and economical feasibility of a project designed to process 45,000 m3 of water per day. Possible effects of a large scale operation on interactions between Petroleum Development Oman and local population are listed, and suggestions on the social processes involved are made. The economics of reed bed water treatment and water consumption through the use of forestry are determined and compared with the current practise of deep well disposal. The economics of the treatment-forestry system are more favorable than the economics of the deep well disposal. The technical analysis shows that the reed beds are able to treat water to remove hydrocarbons, and suggestions for management, design and development of the system are given

A genetic and molecular analysis of two genes involved in flowering initiation of Arabidopsis = [Een genetische en moleculaire analyse van twee genen die betrokken zijn bij de bloei initiatie van Arabidopsis]

The transition from the vegetative to the reproductive phase (flowering initiation) in plants has a complex regulation which is affected by environmental and internal plant factors. The understanding of this process is not only of fundamental interest but could also lead to practical applications. The research into flowering initiation has a long history. The initial emphasis on physiological and biochemical studies led to the identification of different factors that influence flowering time. During the sixties, a genetic approach was initiated in different plant species. In Arabidopsis several late flowering mutants were isolated and genetically and physiologically characterised which revealed a complex regulation of flowering time by different pathways. These are the photoperiodic promotion pathway which promotes flowering under long day light conditions, the vernalisation promotion pathway which promotes flowering by low temperatures and the autonomous promotion pathway which promotes flowering independent of the environment. Due to its favourable genetic and molecular features, research on flowering initiation became focussed on Arabidopsis. Since the beginning of the nineties, several of the genes involved in the different pathways have been cloned, providing more information about the function of these genes in the cell and their relations with each other. Despite this increasing amount of information, the picture is still far from complete.The aim of the work presented in this thesis is to increase our knowledge of flowering time regulation. It focussed on the genetic and molecular characterisation of the semi-dominant mutant fwa , which flowers late under long day light conditions and has been proposed to be part of the photoperiodic promotion pathway. One approach sought to identify additional genes that affect flowering by mutagenesis of the fwa mutant. In addition to three different intragenic revertants of fwa , this screen yielded a novel early flowering mutant.This mutant was named early flowering in short days ( efs ). Its phenotypic characterisation has shown that the main role of the wild-type EFS gene is to delay flowering in plants that have entered the adult vegetative phase, which is considered to be the phase where plants are able to respond to environmental signals in order to flower. Consistent with this, efs mutant plants do not show an early flowering phenotype when grown under environmental conditions that lead to a shortened adult vegetative phase such as long days and vernalisation. To learn more about the role of EFS in relation to other genes involved in flowering initiation, double mutants were isolated. Their characterisation showed that efs is involved in the autonomous promotion pathway. This result, together with the lack of a vernalisation response, suggests that EFS is likely to represent a new element acting at a point close to the convergence of signals from the autonomous promotion pathway and the vernalisation promotion pathway.The main topic of this thesis concerns the map based cloning of the FWA gene. By using plants which have a cross-over between FWA and surrounding markers, the FWA locus could be located in a region of about 60 Kb. Plant transformation experiments with cosmids spanning this region showed that the gene is located in the overlap of two cosmids. This overlap contained only one complete gene that encodes a homeodomain containing transcription factor. The altered expression of this gene in fwa mutants together with DNA mutations in the intragenic revertants of fwa-1 further proved that this gene is FWA .Analysis of FWA revealed several interesting characteristics. Surprisingly, the mutant and wild-type alleles had an identical DNA sequence in the FWA region, excluding DNA mutations in the gene as a cause for the mutant phenotype. Furthermore, two direct repeated sequences were found in the 5' genomic region of FWA . In wild-type plants these repeats were heavily methylated, whereas they were completely un-methylated in the mutant alleles. In contrast to fwa mutant plants, which showed a high expression of FWA at all developmental stages, wild-type plants showed only a low expression of FWA in siliques and germinating seeds. Taken together, these findings suggest that loss of methylation of the FWA repeats in the fwa mutant causes a high level of expression of the gene, leading to a late flowering phenotype. A similar correlation of late flowering, FWA overexpression and hypomethylation of FWA repeats was found in late flowering plants which were derived from the ddm1 hypomethylation mutant. The late flowering phenotype of these plants had previously been mapped to the FWA region. Nevertheless, the correlation between hypomethylation of the FWA repeats and FWA expression was not found in germinating seeds of wild-type plants which showed expression of FWA but methylation of the repeats. Although this expression might come from residual mRNA produced earlier in developing seeds, it is possible that methylation of the repeats does not always prevent expression of FWA . Perhaps a different epigenetic mechanism early in development can induce expression of methylated genes.The correlation of FWA expression with late flowering indicates that FWA is a repressor of flowering. Earlier studies had already shown that FWA does not only play a role in the initiation of flowering but also in flower meristems. However, the FWA transcript was not detected in flower buds or flowers and therefore, FWA might only affect this process when highly expressed in the fwa mutant. Possibly, FWA has no function in flowering initiation of wild-type. It might participate in a seed-specific process, as suggested by its expression in seeds. However, the lack of an obvious phenotype suggests that this role is minor or redundant with other genes.The cloning of FWA revealed that the absence of methylation in the repeating sequences in the 5' region of the FWA gene leads to an enhanced expression in the fwa mutant. However, it did not become clear whether this correlation is direct or indirect. Also the importance of the methylation in wild-type plants is still unclear. It is possible that it has a role in the expression of the gene under specific environmental conditions.The results discussed in this thesis have contributed to the existing knowledge of flowering initiation by the isolation of a mutant at a novel locus and the cloning of a previously known gene which are both involved in this process. In addition, the results suggest a possible role for DNA methylation in gene regulation of Arabidopsis.</p

Utilizing shallow ground water

Presented at Contemporary challenges for irrigation and drainage: proceedings from the USCID 14th technical conference on irrigation, drainage and flood control held on June 3-6, 1998 in Phoenix, Arizona.Includes bibliographical references.Shallow ground water in arid irrigated areas has generally been treated as a waste product of irrigation which was to be discharged into an available water course for ultimate disposal in an ocean. This practice is no longer environmentally acceptable and means need to be developed to minimize the environmental impact of uncontrolled discharge of drainage water from irrigated lands. This paper presents the results of field and theoretical studies which demonstrate methods to reduce and minimize the volume of drainage water for disposal. The field studies demonstrated the use of subsurface drip irrigation with modified crop coefficients to increase the water use from shallow ground water, and the use of control structures on drainage systems to control the depth to shallow ground water to improve the water use by the crop from shallow ground water. Application of these techniques resulted in significant use of ground water by cotton and tomato. The theoretical studies demonstrated that using new drainage design criteria will result in less drainage discharge and lower salt loads. Improved irrigation efficiency will have the largest impact on reducing total drainage discharge

Managing salinity for sustainability of irrigation in areas with shallow saline ground water

Irrigation will be required to meet the demands of the world population for food. Water will also be needed to meet the municipal, industrial, and environmental demands of the growing population. As a result irrigation water supplies will be reduced and irrigators will probably be forced into using degraded water as part of the supply and the possibility for increased salinity in the soil profile will occur. Drainage will be required to assist in the management of the water needed for leaching to prevent soil salinisation. Drainage water containing salt and other contaminants creates a water quality problem for the water body receiving the drainage water. The paper presents the results of three cases studies that address the issue of disposal of saline drainage water through reuse for supplemental irrigation, water table control, and changing the design criteria for subsurface drainage as methods to reduce the drainage volume. The first study demonstrated that over 50% of the crop water requirement can be met with saline drainage water and that salinity in the soil profile can be managed to not adversely affect yields. This is not the case if the drainage water contains high levels of boron. The second study demonstrated that the water table can effectively be manipulated if the drainage system is properly installed. The third study showed the reduction in salt load as a result of implementing drainage control on deep drains or installing shallow drains. The results from these studies demonstrate that irrigated agriculture is sustainable in arid and semi-arid areas through improved management of the subsurface drainage system